Bayesian compositional models for ordinal response.

Ordinal response is commonly found in medicine, biology, and other fields. In many situations, the predictors for this ordinal response are compositional, which means that the sum of predictors for each sample is fixed. Examples of compositional data include the relative abundance of species in microbiome data and the relative frequency of nutrition concentrations. Moreover, the predictors that are strongly correlated tend to have similar influence on the response outcome. Conventional cumulative logistic regression models for ordinal responses ignore the fixed-sum constraint on predictors and their associated interrelationships, and thus are not appropriate for analyzing compositional predictors.To solve this problem, we proposed Bayesian Compositional Models for Ordinal Response to analyze the relationship between compositional data and an ordinal response with a structured regularized horseshoe prior for the compositional coefficients and a soft sum-to-zero restriction on coefficients through the prior distribution. The method was implemented with R package rstan using efficient Hamiltonian Monte Carlo algorithm. We performed simulations to compare the proposed approach and existing methods for ordinal responses. Results revealed that our proposed method outperformed the existing methods in terms of parameter estimation and prediction. We also applied the proposed method to a microbiome study HMP2Data, to find microorganisms linked to ordinal inflammatory bowel disease levels. To make this work reproducible, the code and data used in this paper are available at https://github.com/Li-Zhang28/BCO.

Medical care-seeking behaviours among drowning casualties: Results from a national survey conducted in Bangladesh.

OBJECTIVE: Despite the high magnitude of drowning, medical care-seeking behaviours among drowning casualties remain unexplored in Bangladesh. This study aimed to explore this behaviour among drowning casualties in Bangladesh. METHODS: A population-based cross-sectional study was conducted using a multi-stage cluster sampling method. Data were collected using a structured questionnaire from 299,216 rural and urban residents. RESULTS: From the survey, we found 191 drowning cases: 40.84% (n = 78) were fatal and 59.16% (n = 113) were non-fatal. Among the drowning cases, 71.2% (n = 136) were referred to healthcare providers, while 62.8% (n = 120) received medical care from different health service providers. Further analysis showed that 66.6% (n = 116) of children and 26.6% (n = 4) of adults sought healthcare. As many as 78.9% (n = 120/152) of rural residents sought healthcare, as compared to 61.5% (n = 24/39) of urban residents. Among all drowning casualties, 31.7% (n = 38) received healthcare from a qualified healthcare provider, whereas 68.3% (n = 82) received it from non-qual]ified healthcare providers. About 59 (49%) casualties received care from a pharmacy and 34 (28%) from a recognised hospital. The hospital admission rate for drowning was 11.7%. About 14 (11.7%) drowning casualties were brought to hospitals in motorised or non-motorised vehicles. As many as 97 (80.8%) patients sought healthcare attention and managed to survive. CONCLUSION: A significant number of drowning casualties sought medical care from qualified and non-qualified healthcare providers. In Bangladesh, it is necessary to develop guidelines for providing medical care for drowning casualties.

Effect of Intensive Blood Pressure Lowering on the Risk of Atrial Fibrillation.

It remains uncertain whether intensive control of blood pressure (BP) results in a lower risk of atrial fibrillation (AF) in patients with hypertension. Using data from SPRINT (Systolic Blood Pressure Intervention Trial), which enrolled participants with hypertension at increased risk of cardiovascular disease, we examined whether intensive BP lowering (target systolic BP [SBP] <120 mm Hg), compared with standard BP lowering (target SBP<140 mm Hg), results in a lower risk of AF. This analysis included 8022 participants (4003 randomized to the intensive arm and 4019 to standard BP arm) who were free of AF at the time of enrollment and with available baseline and follow-up electrocardiographic data. AF was ascertained from standard 12-lead electrocardiograms recorded at biannual study examinations and an exit visit. During up to 5.2 years of follow-up and a total of 28 322 person-years, 206 incident AF cases occurred; 88 in the intensive BP-lowering arm and 118 in the standard BP-lowering arm. Intensive BP lowering was associated with a 26% lower risk of developing new AF (hazard ratio, 0.74 [95% CI, 0.56-0.98]; P=0.037). This effect was consistent among prespecified subgroups of SPRINT participants stratified by age, sex, race, SBP tertiles, prior cardiovascular disease, and prior chronic kidney disease when interactions between treatment effect and these subgroups were assessed using Hommel adjusted P values. In conclusion, intensive treatment to a target of SBP <120 mm Hg in patients with hypertension at high risk of cardiovascular disease has the potential to reduce the risk of AF. Registration- URL: https://www.clinicaltrials.gov; Unique identifier: NCT01206062.